Day 14: The Skeleton

An MRI's View

The chicken has grown a LOT! It now is as long as the egg is wide. It is not moving as far as it was two days ago because it is running out of room. But it is still moving enough that most images are blurred. It takes a long time to get a good MRI image now because of how much the chick moves.

The egg compartments have changed a lot too. There no longer is an identifiable yolk. The chick is enclosed by a large dark chamber (amnion? - how did it get so big?) which has little droplets of some other material in it (waste products?). There are two compartments at top and bottom which are brighter. Are these albumen? Or something new? How could you investigate this?

MRI: Front view series:

Here are 4 frames from the front view series. You can make out a few body parts. I am speculating a bit about the wing - it is in almost the right place, but seems to be at an awkward angle.

Compare the positions of the eyes, "wing", heart with the position as seen in the side views, below. Do my interpretations agree with each other? Remember the chick may have moved, but not too far.

MRI: Side view series.

Here are 3 frames from the side view series. Notice the bilateral symmetry of the body - it isn't perfect because the chick is not perfectly aligned with the slice, but (especially in frame 139) you can see matching structures on right and left sides of the body. Note particularly the two thin diagonal black objects at EF-45, and FG-5. Also In frame 144, there are two lighter spots on either side of the "keel" (at upper left corner of E6 and lower right corner of D4.) These might be related to the wings. The keel is the point of attachment for the flight muscles.

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